Method of regulating combustion-engines.



P. G. ROES'TI, METHOD or REGULATING comsusnom ENGINES. I I I APPLICATIONFILED JUNE 6, l9 l2- I 1,166,938, Patented Jan. 4, 1916.

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WITNES I Q P 15tn Trav l,

P. G. HOESTJ.

METHOD OF REGULATING COMBUSTION ENGINES APPLICATION .FILED JUNE 6 1912.I 1,166,938- Patented Jan. 4, 1916.

'2 SHEETS-SHEET 2.

{p EVNTOR .ATTORNEY UNITED STATES PATENT OFFICE.

PAUL G. ROESTI, OF WINTERTHUR, SWITZERLAND, ASSIGNOR TO BUSCH-SULZERBROS.- DIESEL ENGINE COMPANY, OF ST. LOUIS, MISSOURI, A CORPORATION OFMISSOURI.

METHOD OF REGULATING COMBUSTION-ENGINES.

Specification of Letters Patent.

Patented Jan. 4, 1916.

Application filed June 6, 1912. Serial No. 701,994.

To all whom it may concern Be it known that I, PAUL G. RoEsTI, a citizenof the Republic of Switzerland, residing at Winterthur, Canton ofZurich, Switzerland, have invented the followingdescribed Improvementsin Methods of Regulating Combustion-Engines.

The invention seeks to improve the combustion and general efficiency ofcertain types of combustion engines which are required to operate underwidely varying and quickly changing load conditions, and consists in animproved method of controlling the admission of fuel, as will behereinafter fully set forth.

The invention refers to Diesel-type engines wherein the fuel is injectedin atomized form by means of highly compressed air into a body of air orgas previously compressed in the engine cylinder to a temperaturesuflicient to ignite it, the fuel beingadmitted during a part of theworking stroke. Heretofore compensation for load variations insuchengines has been made in part and chiefly by means of correspondingregula tion of the fuel supplied for each stroke.

The present invention consists in a new method of accomplishing moreeffective regulation and compensation for load variations bysimultaneously controlling both the duration of the fuel admissionperiod and the pressure of air by which the fuel is injected against thecylinder compression. Such method may be employed in conjunction withthe customary regulation of the fuel at the pump, and results in amaterial economy of power and an absence of smoke in the exhaust underall conditions of engine operation. 4

In the accompanying drawings, Figure 1 is a diagram representing therelationship of the two controls, z. e., the control of the duration offuel admission, and of the tension of the injection air; Fig. 2.represents the combustion card in relation to such diagrammaticcontrol. Fig. 3 is a view, partly in elevation and partly in section, ofapparatus for carrying out the method, the illus-' tration beingsomewhat schematic.

In Fig. 1' the circle a represents the piston stroke, and the curves 1),c and d indicate the open periods of the fuel valve of the engine fordifferent degrees of load as represented by t, t and t The amount ofval-ire lift of the fuel valve, also represented by these .curves, maybe variable or constant, as preferred, provided, of course, thecross-section of the valve opening is adequately designed. Correspondingto the graded duration of fuel admission the points E E and E representthe corresponding pressures of the fuel injection air, a pressure of,say, 38 atmospheres" being employed for the lighter load (curve 12), 45atmospheres for the intermediate load (curve a) and 60 atmospheres forthehcaviest load (curve (Z) as plainly indicated on the diagram andshown by the legends thereon. Forv average load conditions the variationof the injection air pressure may be made in direct proportion to thesimultaneous variation of the duration of fuel admission, but above orbelow the range of what may be regarded as average load fluctuations,the change in the air pressure should take place in 'an increasingproportion relatively to that of the admission period. But suchvariation of the air pressure, as I have ascertained, must also beconfined within certain definite outside limits above or beyond whichonly the period of fuel admission shouldbe further varied. Thus startingwith the engine running at an average load, and upon a decrease thereof,fuel admission and injection air pressure are simultaneously diminishedand in direct proportion, down to the point which is taken for thelowest ordinary load beyond which the air pressure must be diminishedmore rapidly than the fuel admission until the point of relatively lightload is reached, beyond which the air pressure must remain constantwhile the fuel admission period may be further shortened until the loadbecomes zero. The same regulation takes place in thereverse sense withan increasing load. The particular duration of fuel admission and thecorresponding air tension for different load conditions, as well as thelimits above referred to, are best determined empirically in the mannerthat will be well understood, and when once determined can thereafter bearranged to be established automatically by means of any suitable formof gearing.

, The control of the injection air pressure, for instance, may beproduced by means of a multiple-way valve interposed between the enginefuel valve and a battery of air tanks pressures, such valve beingadapted to connect any one of these Sources with the fuel valve for thepurpose of injecting the fuel. The handle of such valve may be actuatedby or in conjunction with the control of the fuel admission controllingapparatus, whereby when it reaches its predetermined limit of movement,representing the limit of change of injection air pressure, the lattermay be further moved to still further increase or decrease the durationof the admission period. Conveniently a single control member will.operate both or all of the regulating devices of the engine, and suchmember may be operated by handor by'means of a governor or indirectly bysome organ which is regulated in conformity -with the load on theengine, as, for instance, by the pressure condition in the injection airpump, the latter in such case being directly controlled.

It will be observed that the new method requires that the variation ofthe injection pressure and the valve motion be simultaneous, which factreduces to the minimum the possibility of failure or accidentaldisturbance of regulation of the engine, by the failure of one of thecontrolling factors, inasmuch as such disturbance will be lessened bythe continuing action of the other members. It will also be observedthat the invention provides for the most favorable use of air pressureand permits the employment of diiferent kinds of fuel for differentloads, affording facilities for the proper injection pressure for eachgrade of fuel.

Fig. 2 shows for instance one arrangement of the subject-of invention,In the drawing a represents a Diesel engine, 6 its fuel valve throughwhich the fuel is injected by means of highly compressed air. Theinjecting air is supplied by a two-stage compressor c, d, 0 being thelow and d the highv pressure stage. The air suction pipe 6 is fittedwith a valve f which may be operated either by hand or by means of agovernor.

The position of this valve is thus according to the output of engine. Inthe accompanying drawing valve f is shown to be connected to a governorg by gear h. This injection air passes from the high pressure air pumpthrough pipe 2' over to the fuel valve 6. The

time of keeping this valve I) open depends on the load on the engine,the result being variable duration of admission. The same effect can beobtained by different means, for instance like in steam engines. F orthis reason no special arrangement of saidgear has been shown. Themotion for this gear can be derived from; the governor. It is desirableto fit the high pressure pipe 2' with means for cooling the air and adda receiver of sufficient capacity as shown by dotted lines. Anautomatically working apparatus is'provided in high pressure pipe 71 fordirectly regulating the pressure. This latter consists of, a regulatingelement Z, which varies, according to its position, the flow of the highpressure air toward the fuel valve and also the pressure of theinjection air. The automatic regulation of this throttle valve isperformed by the piston m, the motion of which is transmitted to thethrottle mechanism Zloy the linkage n. The piston m is put under airpressure through the pipe 0 and takes its position accordingly. By thepressure in 0, which varies with the output of the engine, acting inopposition to the pressure of the spring p, the piston m is held incertain positions and with this the mechanism Z. The pipe 0 is connectedsomewhere to the suction pipe or to any other pipe between two stages ofthe injection air pump. In our drawing it is shown con nected to thedischarge pipe of the first stage 0. The connection could for instancealso be made to the suction pipe 6, on condition however that it joinsbetween the regulating valve f and low pressure pump itself, the reasonsof which are obvious.

Thisimproved regulating device acts as follows: Supposing an alterationof the horse power output of the machine occurs. The regulator 9 willchange its position forthwith operating thereby also the gear of thefuel valve of the fuel pump and of the valve f in the suction air pipe.The quantity of air sucked in by the pump as well as the suctionpressure will adjust themselves automatically to a certain value, withthe result that a change of pressure in the discharge pipes of ,thedifl'erent air pump stages 0 and d will take place. As therearereceivers and intercoolers, etc., between the different compressorstages, some time will elapse before apressure in the fuel valve and inthe pipe 2', leading to same, is obtained, which corresponds to theposition of mechanism f. In order to perform an alteration of pressurein the air injection pipe 2' more quickly, as well as in the fuel valve2') itself, the throttle mechanism Z is provided, which is adjusted bythe'piston m, the latter being dependent on the air pressure of the lowpressure stage and operated by same. According to the various positionsof valve f, the pressure in the low pressure stage 0 changes relativelyquick, whereby a quick alteration, of pressure occurs in the highpressure pipe 2'. The effect of organ Z can be increased by insertingsame between vessel k and fuel valve b, but not between vessel 7c andhigh pressure stage at of the injection air compressor, for then onlythe pressure of a relatively small volume of the pipe 2' has to bechanged. In order to insure the passage of a certainouantity ofinjection air for a given load, or for instance for no load at all, aby-pass pipe q may be fitted to the regulation organ Z, always allowingthe passage a minimum quantity of air. .The adjustment of this said flowof air can, if. for 0 instance conditions of load are changed, be variedand can be determined by a regulating organ r. Any other organ, as forinstance, a membrane, may be used instead of piston m. .Onmulti-cylinder engines each cylinder or group thereof or all cylinderstogether may be fitted with such a regulating arrangement.

I claim' 1. A- method of operating internal combustion engines whichcomprises introducing air or gas into the engine cylinder, compressingthe same therein, injecting fuel by means of air under pressure into thebody of air or gas prevlously compressed in the cyhnder, andcompensating for load variations by simultaneously and similarly varyingthe duration of the period of fuel injection and the tension of the fuelinjection air.

"of air or gas previously compressed in the cylinder, and compensatingfor load variations by simultaneously and similarly varying the durationof the period of fuel injection and the tension of the fuel injectionair within certain limits and above or below such limits varying theduration of the 'pe riod of fuel injection only.

In testimony whereof, I have signed this specification in the presenceof two witnesses. PAUL G. ROESTI.

WVitnesses.

' AUGUST RUEGG,

HARRY A. MCBRIDE.

